The invention relates to a method of treating gas condensates from a coking process or other processes of thermally upgrading coal.
During the thermal decomposition of bituminous coal in a coke oven, crude gas (coke-oven gas) is obtained in an amount and composition depending on the respective operating conditions and the nature of the coal undergoing carbonization. Component substances of the gas are, among others, CO.sub.2, CO, H.sub.2, CH.sub.4, C.sub.n H.sub.m, N.sub.2 and O.sub.2. The crude gas contains tar, crude benzene, crude naphthalene, ammonia, and hydrogen sulfide. The gas further contains a substantial proportion of water vapor. The water vapor content of the gas includes the water content of the raw material, i.e. of the coal, and water of formation which is produced during the thermal decomposition of the coal in the coke oven by a partial oxidation of the hydrogen contained in the coal.
As the gases cool down, condensates form which are loaded to different degrees with components, depending on the raw materials and operating conditions during the carbonization. Substantial components of the condensates are sedimentary substances and substances which remain in suspension, as well as tar oils. Further formed in the gas condensates are phenols, pyridine, and some amounts of salts.
While processing coke oven gases, further condensates are obtained at various locations. This occurs, for example, in the benzene treatment, the sulfuric acid plant, and the gas compression.
The obtained gas condensates are processed as far as possible, to minimize the amount of waste water. With this in mind, a waste water free carbonization method has been sought in the past, with the use of the treated gas condensate as coke quenching water. This method could not prevail since the salt content, particularly of chlorides, of the gas condensates was too high.